1. Field of the Invention
The present invention relates to a video data editing apparatus on the other side of the re-encoded data that edits an optical disc that records video data files, and to a computer-readable recording medium that stores an editing program.
2. Description of the Background Art
Video editors in the film and broadcasting industries make full use of their skill and experience when editing the great variety of video productions that reach the market. While movie fans and home video makers may not possess such skill or experience, many are still inspired by professional editing to try video editing for themselves. This creates a demand for a domestic video editing apparatus that can perform advanced video editing while still being easy to use.
While video editing generally involves a variety of operations, domestic video editing apparatuses that are likely to appear on the market in the near future will especially require an advanced scene linking function. Such function links a number of scenes to form a single work.
When linking scenes using conventional domestic equipment, the user connects two video cassette recorders to form a dubbing system. The operations performed when linking scenes using this kind of dubbing system are described below.
FIG. 1A shows a video editing setup using video cassette recorders that are respectively capable of recording and playing back video signals. The setup of FIG. 1A includes the video cassette 301 that records the source video, the video cassette 302 for recording the editing result, and two video cassette recorders 303 and 304 for playing back and recording video images on the video cassettes 301 and 302. In this example, the user attempts to perform the editing operation shown in FIG. 1B using the setup of FIG. 1A.
FIG. 1B show the relationship between the material to be edited and the editing result. In this example, the user plays back scene 505 that is located between time t5 and time t10 of the source material, scene 506 that is located between time t13 and t21, and scene 507 that is located between time t23 and t25 and attempts to produce an editing result that is only composed of these scenes.
With the setup of FIG. 1A, the user sets the video cassette 301 including the source material into the video cassette recorder 303 and the video cassette 302 for recording the editing result into the video cassette recorder 304.
After setting the video cassettes 301 and 302, the user presses the fast-forward button on the operation panel of the video cassette recorder 303 (as shown by 1 in FIG. 1A) to search for the start of scene 505. Next, the user presses the play button on the operation panel of the video cassette recorder 303 (as shown by 2 in FIG. 1A) to reproduce scene 505. At the same time, the user presses the record button on the operation panel of the video cassette recorder 304 (as shown by 3 in FIG. 1A) to commence recording When scene 505 has finished, the user stops the operation of both video cassette recorders 303 and 304. The user then fast-forwards the video cassette to the start of scene 506, and then simultaneously commences the playback by video cassette recorder 303 and the recording by video cassette recorder 304. After completing the above process for scenes 506 and 507, the user has the video cassette recorders 303 and 304 respectively rewind the video cassettes 301 and 302 to complete the editing operation.
If the scene linking operation described above could be performed with ease at the home, users would then be able to easily manage programs that have been recorded on a large number of magnetic tape cassettes. However, when the user wishes to perform a scene linking operation, the user has to repeat the processes of locating the start of the desired scene in the source material and reproducing all of the video images from the beginning to the end of the scene for each scene to be linked. Accordingly, video editing is a burdensome process.
Exceeding the potential of video cassettes, file systems that treat audio video data (AV data), that is produced by multiplexing video data and audio data, in the same way as computer files have been subject to increasing attention for their ability to facilitate video editing.
The file systems referred to here are data constructions for managing areas on a recording medium, like a hard disc or optical disc, that allows random access. A file system divides the entire disc area into data blocks that are several dozen KB in size, with the data blocks that do not contain valid data being managed as an empty areas. When a file is deleted, the data blocks that stored the file are registered as empty areas.
Data is generated by an application program operating within the file system, and when the user gives an indication to have this data recorded as a file on a recordable disc, the file system calculates the size of the file, and judges whether there is a continuous empty area on the disc whose size is equal to or greater than the size of the file.
If such an area is present on the disc, the file system will record the file in this area, though if there is no empty area as long as the file on the disc, the file system will look for fragmented empty areas on the disc. The file system then divides data to be recorded and stores the different sets of divided data in different empty areas on the disc. The file system then generates management information for managing the sets of divided data as different sets of data, and has the management information written onto the recordable disc to complete the recording of the file on the optical disc.
Since the data that is recorded by the file system is divided into a plurality of sets of data and stored as fragments in different areas on the disc, it is not necessary for the recordable optical disc to include an continuous empty area that is as large as the file. Even if the data to be recorded is AV data, this data can still be efficiently recorded on the optical disc.
However, when a plurality of sets of AV data are recorded on a recordable optical disc under the control of a file system, if the continuous length of an area storing the AV data is too short, when the AV data in this area is reproduced, there is the risk that the display of video images will be interrupted while the optical pickup is jumping from the data to the recording position of the following AV data.
In more detail, the reproduction apparatus reads the video images stored on the recordable optical disc into temporary buffer and the AV decoder of the reproduction apparatus decodes the AV data read into the buffer When the area recording AV has a long continuous length, a sufficient amount of AV data can be accumulated in the buffer. When the optical pickup then jumps to a different recording position, there will be sufficient data in the buffer for the decoder to continue its decoding process, meaning that the display of video images can be continued without interruption.
On the other hand, when video editing is performed and operations that take one part of the existing AV data and use it to create a new file are repeated a large number of times, many short sets of data will end up on the recordable disc. Since the continuous length of the recording areas that record these sets of AV data are short, an insufficient amount of data will be accumulated in the buffer when such data is reproduced. If the optical pickup jumps to another recording position with only a small amount of data in the buffer, an underflow will occur in the buffer, so that the continuity of the decoding of AV data by the buffer cannot be maintained. This will result in an interruption in the video display.